In New Zealand we have 91 octane, 96 Octane and 98 Octane unleaded Petrol. We have supplies of 120 octane that can be bought in 20litre containers and added to vehicles (illegal).
At the moment the 91 Octane is selling at $1.60 per litre.
As I drive old Rovers with no depreciation and low insurance costs...who cares what the cost is..the enjoymment is the main force for me..not the Petrol.
Rob